Am I alone in thinking these are (expensive) cheap shit?

Eldest has bought a 2007 ST, one owner from new and with FSH including all the receipts.

The previous owner replaced two of the centres, but they are already bubbling round the outside, like melted plastic, even though they seem to have aluminium covers. My guess is that the aluminium is oxidising and bubbling the lacquer coat.

First thought was just to buy new ones but I have two problems with that:
They are almost £20 each, and
They seem to fall off or get stolen very easily.

Anyone else noticed this, or have any suggestions on how to refurb or to make them a bit more secure?